Chelsea are preparing a bid of £20 million to try to sign Wayne Rooney in the January transfer window.

Although the offer would fall far short of the expected £35 million bid by Manchester City, sources suggested on Tuesday night that Chelsea believe they may be favourites to secure the Manchester United striker because Sir Alex Ferguson would rather sell to them.

Indeed it is understood that Chelsea have been closely tracking Rooney's situation for several months after being alerted that he may not be happy at Old Trafford and was open to the idea of leaving with less than two years on his contract.

Real Madrid are the only other club seriously in the running to sign the 24 year-old, but it is uncertain what kind of offer they are considering, especially as they would prefer to wait until the summer before making a move.

United will make it clear to all suitors that they want to do a deal sooner than that. This is largely because the value of striker will have diminished by the end of the season, when he will enter the final year of his contract, and also because Ferguson has decided he wants the player to leave as soon as possible to cause minimum disruption.

Although Rooney is, according to sources, "100 per cent sure he wants to move" and is prepared to join City, who will also offer him by far the biggest wages, he is believed to be keen on Chelsea.

Ferguson, who has been given a mandate to sell by United's American owners the Glazers, would ideally prefer Rooney to leave the Premier League and move abroad.

Real are the most likely to make an offer and there are undoubtedly players, particularly Karim Benzema and Kaka, in whom United would be interested, especially as it is understood that a straight cash deal would involve a large portion of the money going to Everton as a sell-on fee, believed to be 25 per cent of any profit United make on Rooney.

Real have already made it known that they are looking to offload certain players, and that list includes Lassana Diarra and Fernando Gago. However, Rooney has also indicated he would rather stay in England.

Chelsea's interest in Rooney is long-standing and manager Carlo Ancelotti, who is pushing for the signing, is an avowed fan, having praised the striker last season for his performances. On the eve of Chelsea's Champions League tie against Spartak Moscow, Ancelotti admitted he would be interested.

Chelsea owner Roman Abramovich is, according to sources close to him, still hoping to sign Fernando Torres having had a long-standing interest in the Liverpool striker.

A bid was lodged in the summer, and although this fell below Liverpool's valuation, the club's plight, and the Spaniard's unhappiness, may lead to Chelsea making a renewed offer in the next transfer window.

It is not beyond the realms of possibility that they could bid for both Rooney and Torres, with one source suggesting on Tuesday that this was "Roman's dream".

Quite where that would leave Didier Drogba and Nicolas Anelka remains to be seen, although Chelsea are acutely aware that they will have to eventually replace their main strikers, who are both over 30.

The likelihood is that Chelsea will not offer enough for Rooney to convince United to sell to them, rather than City. It will also be difficult to persuade Abramovich to increase his bid given the player's contract situation and the personal problems he has faced.

He will want to drive a hard bargain for Rooney, who could buy himself out of the final year of his deal for about £5 million next summer. "Why would someone pay the market rate right now?" one source said on Tuesday night.

Tottenham manager Harry Redknapp alluded to this on Tuesday night when he said: "It's an amazing situation that Rooney could become a free agent, someone who is worth £50-60 million.

"He's in a situation whereby if he does not want to sign a contract then in 18 months he is a free agent. He's in a position where if someone gives him personally £30 million then he is still a cheap player. He can go down that road and Man United can do nothing about it."